Comparing Water Vapour Thermal Therapy (Rezūm) and TURP

This is a randomized controlled trial using a non-inferiority design with the subjects randomized 1:1 to either water vapour thermal treatment (REZUM) arm or transurethral resection of prostate (TURP) arm.

Inclusion Criteria: * Men 50-80 years * Refractory urinary retention related to benign prostatic hyperplasia (BPH) * On urethral Foley's catheter before treatment * Prostate size 30-80ml on ultrasound Exclusion Criteria: * Prior prostate operation * Past or current history of prostate cancer * Strong suspicion of prostate cancer (e.g. Elevated PSA before urinary retention or abnormal prostate on DRE without workup for prostate cancer) * Known Urethral stricture / Bladder stone / Hypocontractile bladder * Known neurological diseases which may affect bladder function (e.g. Parkinsonism, stroke) * Contraindicated to undergo TURP or REZUM (e.g. not fit for GA/SA, active urinary tract infection, fail to be placed in lithotomy position, uncorrectable coagulopathy, antiplatelet or anticoagulant which cannot be stopped)